/**
 * 工具函数库
 */

/**
 * MD5加密函数
 * @param {String} string - 要加密的字符串
 * @returns {String} - MD5加密后的字符串
 */
export const md5 = (string) => {
  function md5cycle(x, k) {
    var a = x[0], b = x[1], c = x[2], d = x[3];
    a = ff(a, b, c, d, k[0], 7, -680876936);
    d = ff(d, a, b, c, k[1], 12, -389564586);
    c = ff(c, d, a, b, k[2], 17, 606105819);
    b = ff(b, c, d, a, k[3], 22, -1044525330);
    a = ff(a, b, c, d, k[4], 7, -176418897);
    d = ff(d, a, b, c, k[5], 12, 1200080426);
    c = ff(c, d, a, b, k[6], 17, -1473231341);
    b = ff(b, c, d, a, k[7], 22, -45705983);
    a = ff(a, b, c, d, k[8], 7, 1770035416);
    d = ff(d, a, b, c, k[9], 12, -1958414417);
    c = ff(c, d, a, b, k[10], 17, -42063);
    b = ff(b, c, d, a, k[11], 22, -1990404162);
    a = ff(a, b, c, d, k[12], 7, 1804603682);
    d = ff(d, a, b, c, k[13], 12, -40341101);
    c = ff(c, d, a, b, k[14], 17, -1502002290);
    b = ff(b, c, d, a, k[15], 22, 1236535329);
    a = gg(a, b, c, d, k[1], 5, -165796510);
    d = gg(d, a, b, c, k[6], 9, -1069501632);
    c = gg(c, d, a, b, k[11], 14, 643717713);
    b = gg(b, c, d, a, k[0], 20, -373897302);
    a = gg(a, b, c, d, k[5], 5, -701558691);
    d = gg(d, a, b, c, k[10], 9, 38016083);
    c = gg(c, d, a, b, k[15], 14, -660478335);
    b = gg(b, c, d, a, k[4], 20, -405537848);
    a = gg(a, b, c, d, k[9], 5, 568446438);
    d = gg(d, a, b, c, k[14], 9, -1019803690);
    c = gg(c, d, a, b, k[3], 14, -187363961);
    b = gg(b, c, d, a, k[8], 20, 1163531501);
    a = gg(a, b, c, d, k[13], 5, -1444681467);
    d = gg(d, a, b, c, k[2], 9, -51403784);
    c = gg(c, d, a, b, k[7], 14, 1735328473);
    b = gg(b, c, d, a, k[12], 20, -1926607734);
    a = hh(a, b, c, d, k[5], 4, -378558);
    d = hh(d, a, b, c, k[8], 11, -2022574463);
    c = hh(c, d, a, b, k[11], 16, 1839030562);
    b = hh(b, c, d, a, k[14], 23, -35309556);
    a = hh(a, b, c, d, k[1], 4, -1530992060);
    d = hh(d, a, b, c, k[4], 11, 1272893353);
    c = hh(c, d, a, b, k[7], 16, -155497632);
    b = hh(b, c, d, a, k[10], 23, -1094730640);
    a = hh(a, b, c, d, k[13], 4, 681279174);
    d = hh(d, a, b, c, k[0], 11, -358537222);
    c = hh(c, d, a, b, k[3], 16, -722521979);
    b = hh(b, c, d, a, k[6], 23, 76029189);
    a = hh(a, b, c, d, k[9], 4, -640364487);
    d = hh(d, a, b, c, k[12], 11, -421815835);
    c = hh(c, d, a, b, k[15], 16, 530742520);
    b = hh(b, c, d, a, k[2], 23, -995338651);
    a = ii(a, b, c, d, k[0], 6, -198630844);
    d = ii(d, a, b, c, k[7], 10, 1126891415);
    c = ii(c, d, a, b, k[14], 15, -1416354905);
    b = ii(b, c, d, a, k[5], 21, -57434055);
    a = ii(a, b, c, d, k[12], 6, 1700485571);
    d = ii(d, a, b, c, k[3], 10, -1894986606);
    c = ii(c, d, a, b, k[10], 15, -1051523);
    b = ii(b, c, d, a, k[1], 21, -2054922799);
    a = ii(a, b, c, d, k[8], 6, 1873313359);
    d = ii(d, a, b, c, k[15], 10, -30611744);
    c = ii(c, d, a, b, k[6], 15, -1560198380);
    b = ii(b, c, d, a, k[13], 21, 1309151649);
    a = ii(a, b, c, d, k[4], 6, -145523070);
    d = ii(d, a, b, c, k[11], 10, -1120210379);
    c = ii(c, d, a, b, k[2], 15, 718787259);
    b = ii(b, c, d, a, k[9], 21, -343485551);
    x[0] = add32(a, x[0]);
    x[1] = add32(b, x[1]);
    x[2] = add32(c, x[2]);
    x[3] = add32(d, x[3]);
  }

  function cmn(q, a, b, x, s, t) {
    a = add32(add32(a, q), add32(x, t));
    return add32((a << s) | (a >>> (32 - s)), b);
  }

  function ff(a, b, c, d, x, s, t) {
    return cmn((b & c) | ((~b) & d), a, b, x, s, t);
  }

  function gg(a, b, c, d, x, s, t) {
    return cmn((b & d) | (c & (~d)), a, b, x, s, t);
  }

  function hh(a, b, c, d, x, s, t) {
    return cmn(b ^ c ^ d, a, b, x, s, t);
  }

  function ii(a, b, c, d, x, s, t) {
    return cmn(c ^ (b | (~d)), a, b, x, s, t);
  }

  function md51(s) {
    var n = s.length,
      state = [1732584193, -271733879, -1732584194, 271733878], i;
    for (i = 64; i <= s.length; i += 64) {
      md5cycle(state, md5blk(s.substring(i - 64, i)));
    }
    s = s.substring(i - 64);
    var tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
    for (i = 0; i < s.length; i++)
      tail[i >> 2] |= s.charCodeAt(i) << ((i % 4) << 3);
    tail[i >> 2] |= 0x80 << ((i % 4) << 3);
    if (i > 55) {
      md5cycle(state, tail);
      for (i = 0; i < 16; i++) tail[i] = 0;
    }
    tail[14] = n * 8;
    md5cycle(state, tail);
    return state;
  }

  function md5blk(s) {
    var md5blks = [], i;
    for (i = 0; i < 64; i += 4) {
      md5blks[i >> 2] = s.charCodeAt(i)
        + (s.charCodeAt(i + 1) << 8)
        + (s.charCodeAt(i + 2) << 16)
        + (s.charCodeAt(i + 3) << 24);
    }
    return md5blks;
  }

  var hex_chr = '0123456789abcdef'.split('');

  function rhex(n) {
    var s = '', j = 0;
    for (; j < 4; j++)
      s += hex_chr[(n >> (j * 8 + 4)) & 0x0F]
        + hex_chr[(n >> (j * 8)) & 0x0F];
    return s;
  }

  function hex(x) {
    for (var i = 0; i < x.length; i++)
      x[i] = rhex(x[i]);
    return x.join('');
  }

  function add32(a, b) {
    return (a + b) & 0xFFFFFFFF;
  }

  return hex(md51(string));
}

/**
 * 存储数据到本地
 * @param {String} key - 键名
 * @param {Any} data - 要存储的数据
 */
export const setStorage = (key, data) => {
  try {
    uni.setStorageSync(key, data)
  } catch (e) {
    console.error('setStorage error:', e)
  }
}

/**
 * 从本地获取数据
 * @param {String} key - 键名
 * @returns {Any} - 存储的数据
 */
export const getStorage = (key) => {
  try {
    return uni.getStorageSync(key)
  } catch (e) {
    console.error('getStorage error:', e)
    return null
  }
}

/**
 * 从本地移除数据
 * @param {String} key - 键名
 */
export const removeStorage = (key) => {
  try {
    uni.removeStorageSync(key)
  } catch (e) {
    console.error('removeStorage error:', e)
  }
}

/**
 * 清空本地存储
 */
export const clearStorage = () => {
  try {
    uni.clearStorageSync()
  } catch (e) {
    console.error('clearStorage error:', e)
  }
}

/**
 * 格式化日期
 * @param {Date|Number|String} date - 日期对象、时间戳或日期字符串
 * @param {String} format - 格式化模板，如 'YYYY-MM-DD HH:mm:ss'
 * @returns {String} - 格式化后的日期字符串
 */
export const formatDate = (date, format = 'YYYY-MM-DD') => {
  if (!date) return ''
  
  let dateObj
  if (typeof date === 'string') {
    dateObj = new Date(date.replace(/-/g, '/'))
  } else if (typeof date === 'number') {
    dateObj = new Date(date)
  } else {
    dateObj = date
  }
  
  if (!(dateObj instanceof Date) || isNaN(dateObj.getTime())) {
    return ''
  }
  
  const year = dateObj.getFullYear()
  const month = dateObj.getMonth() + 1
  const day = dateObj.getDate()
  const hours = dateObj.getHours()
  const minutes = dateObj.getMinutes()
  const seconds = dateObj.getSeconds()
  
  const formatObj = {
    YYYY: year,
    MM: month < 10 ? `0${month}` : month,
    DD: day < 10 ? `0${day}` : day,
    HH: hours < 10 ? `0${hours}` : hours,
    mm: minutes < 10 ? `0${minutes}` : minutes,
    ss: seconds < 10 ? `0${seconds}` : seconds
  }
  
  return format.replace(/(YYYY|MM|DD|HH|mm|ss)/g, (match) => formatObj[match])
}

/**
 * 将时间戳转换为日期
 * @param {Number} timestamp - 时间戳（秒）
 * @param {String} format - 格式化模板
 * @returns {String} - 格式化后的日期字符串
 */
export const timestampToDate = (timestamp, format = 'YYYY-MM-DD') => {
  if (!timestamp) return ''
  return formatDate(timestamp * 1000, format)
}

/**
 * 格式化金额
 * @param {Number} amount - 金额
 * @param {Number} decimals - 小数位数
 * @returns {String} - 格式化后的金额字符串
 */
export const formatAmount = (amount, decimals = 2) => {
  if (amount === undefined || amount === null) return '0.00'
  return parseFloat(amount).toFixed(decimals)
}

/**
 * 格式化手机号码
 * @param {String} phone - 手机号码
 * @returns {String} - 格式化后的手机号码
 */
export const formatPhone = (phone) => {
  if (!phone) return ''
  return phone.replace(/^(\d{3})\d{4}(\d{4})$/, '$1****$2')
}

/**
 * 格式化银行卡号
 * @param {String} cardNo - 银行卡号
 * @returns {String} - 格式化后的银行卡号
 */
export const formatBankCard = (cardNo) => {
  if (!cardNo) return ''
  return cardNo.replace(/\s/g, '').replace(/(\d{4})(\d{4})(\d{4})(\d+)/, '$1 $2 $3 $4')
}

/**
 * 检查是否为微信环境
 * @returns {Boolean} - 是否为微信环境
 */
export const isWechat = () => {
  const ua = navigator.userAgent.toLowerCase()
  return ua.indexOf('micromessenger') !== -1
}

/**
 * 检查是否为支付宝环境
 * @returns {Boolean} - 是否为支付宝环境
 */
export const isAlipay = () => {
  const ua = navigator.userAgent.toLowerCase()
  return ua.indexOf('alipayclient') !== -1
}

/**
 * 获取URL参数
 * @param {String} name - 参数名
 * @returns {String|null} - 参数值
 */
export const getQueryString = (name) => {
  const reg = new RegExp('(^|&)' + name + '=([^&]*)(&|$)', 'i')
  const r = window.location.search.substr(1).match(reg)
  if (r != null) return decodeURIComponent(r[2])
  return null
}

/**
 * 防抖函数
 * @param {Function} fn - 要执行的函数
 * @param {Number} delay - 延迟时间（毫秒）
 * @returns {Function} - 防抖后的函数
 */
export const debounce = (fn, delay = 300) => {
  let timer = null
  return function(...args) {
    if (timer) clearTimeout(timer)
    timer = setTimeout(() => {
      fn.apply(this, args)
    }, delay)
  }
}

/**
 * 节流函数
 * @param {Function} fn - 要执行的函数
 * @param {Number} interval - 间隔时间（毫秒）
 * @returns {Function} - 节流后的函数
 */
export const throttle = (fn, interval = 300) => {
  let lastTime = 0
  return function(...args) {
    const nowTime = Date.now()
    if (nowTime - lastTime >= interval) {
      fn.apply(this, args)
      lastTime = nowTime
    }
  }
}

/**
 * 深拷贝对象
 * @param {Object} obj - 要拷贝的对象
 * @returns {Object} - 拷贝后的对象
 */
export const deepClone = (obj) => {
  if (obj === null || typeof obj !== 'object') return obj
  const result = Array.isArray(obj) ? [] : {}
  for (const key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      result[key] = deepClone(obj[key])
    }
  }
  return result
}

/**
 * 随机生成指定长度的字符串
 * @param {Number} length - 字符串长度
 * @returns {String} - 随机字符串
 */
export const randomString = (length = 16) => {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
  let result = ''
  for (let i = 0; i < length; i++) {
    result += chars.charAt(Math.floor(Math.random() * chars.length))
  }
  return result
}

/**
 * 检查对象是否为空
 * @param {Object} obj - 要检查的对象
 * @returns {Boolean} - 是否为空对象
 */
export const isEmptyObject = (obj) => {
  if (!obj || typeof obj !== 'object') return true
  return Object.keys(obj).length === 0
}

/**
 * 获取文件扩展名
 * @param {String} filename - 文件名
 * @returns {String} - 文件扩展名
 */
export const getFileExtension = (filename) => {
  if (!filename || typeof filename !== 'string') return ''
  return filename.slice((filename.lastIndexOf('.') - 1 >>> 0) + 2)
}

/**
 * 计算两个日期之间的天数
 * @param {Date|String|Number} startDate - 开始日期
 * @param {Date|String|Number} endDate - 结束日期
 * @returns {Number} - 天数差
 */
export const daysBetween = (startDate, endDate) => {
  const start = new Date(startDate)
  const end = new Date(endDate)
  const diffTime = Math.abs(end - start)
  return Math.ceil(diffTime / (1000 * 60 * 60 * 24))
}

/**
 * 将对象转换为查询字符串
 * @param {Object} obj - 要转换的对象
 * @returns {String} - 查询字符串
 */
export const objectToQueryString = (obj) => {
  if (!obj || typeof obj !== 'object') return ''
  return Object.keys(obj)
    .filter(key => obj[key] !== undefined && obj[key] !== null)
    .map(key => `${encodeURIComponent(key)}=${encodeURIComponent(obj[key])}`)
    .join('&')
}

/**
 * 将查询字符串转换为对象
 * @param {String} queryString - 查询字符串
 * @returns {Object} - 转换后的对象
 */
export const queryStringToObject = (queryString) => {
  if (!queryString || typeof queryString !== 'string') return {}
  const query = queryString.startsWith('?') ? queryString.substring(1) : queryString
  const result = {}
  query.split('&').forEach(part => {
    if (!part) return
    const [key, value] = part.split('=')
    result[decodeURIComponent(key)] = decodeURIComponent(value || '')
  })
  return result
}

export default {
  md5,
  setStorage,
  getStorage,
  removeStorage,
  clearStorage,
  formatDate,
  timestampToDate,
  formatAmount,
  formatPhone,
  formatBankCard,
  isWechat,
  isAlipay,
  getQueryString,
  debounce,
  throttle,
  deepClone,
  randomString,
  isEmptyObject,
  getFileExtension,
  daysBetween,
  objectToQueryString,
  queryStringToObject
}